Merge pull request #821 from helix-editor/idle-timer

Idle timer / Autocompletion

7 files changed, 140 insertions, 16 deletions

diff --git a/book/src/configuration.md b/book/src/configuration.md
index 60b12bfd..f30146dd 100644
--- a/book/src/configuration.md
+++ b/book/src/configuration.md
@@ -19,6 +19,7 @@ To override global configuration parameters, create a `config.toml` file located
 | `line-number` | Line number display (`absolute`, `relative`) | `absolute` |
 | `smart-case` | Enable smart case regex searching (case insensitive unless pattern contains upper case characters) | `true` |
 | `auto-pairs` | Enable automatic insertion of pairs to parenthese, brackets, etc. | `true` |
+| `idle-timeout` | Time in milliseconds since last keypress before idle timers trigger. Used for autocompletion, set to 0 for instant. | `400` |
 
 ## LSP
 
diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 6206e6f2..c39a9173 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -199,6 +199,11 @@ impl Application {
                     self.jobs.handle_callback(&mut self.editor, &mut self.compositor, callback);
                     self.render();
                 }
+                _ = &mut self.editor.idle_timer => {
+                    // idle timeout
+                    self.editor.clear_idle_timer();
+                    self.handle_idle_timeout();
+                }
             }
         }
     }
@@ -228,6 +233,38 @@ impl Application {
         }
     }
 
+    pub fn handle_idle_timeout(&mut self) {
+        use crate::commands::{completion, Context};
+        use helix_view::document::Mode;
+
+        if doc_mut!(self.editor).mode != Mode::Insert {
+            return;
+        }
+        let editor_view = self
+            .compositor
+            .find(std::any::type_name::<ui::EditorView>())
+            .expect("expected at least one EditorView");
+        let editor_view = editor_view
+            .as_any_mut()
+            .downcast_mut::<ui::EditorView>()
+            .unwrap();
+
+        if editor_view.completion.is_some() {
+            return;
+        }
+
+        let mut cx = Context {
+            register: None,
+            editor: &mut self.editor,
+            jobs: &mut self.jobs,
+            count: None,
+            callback: None,
+            on_next_key_callback: None,
+        };
+        completion(&mut cx);
+        self.render();
+    }
+
     pub fn handle_terminal_events(&mut self, event: Option<Result<Event, crossterm::ErrorKind>>) {
         let mut cx = crate::compositor::Context {
             editor: &mut self.editor,
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index c1fd7bfe..95c46a4e 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -4051,7 +4051,7 @@ fn remove_primary_selection(cx: &mut Context) {
     doc.set_selection(view.id, selection);
 }
 
-fn completion(cx: &mut Context) {
+pub fn completion(cx: &mut Context) {
     // trigger on trigger char, or if user calls it
     // (or on word char typing??)
     // after it's triggered, if response marked is_incomplete, update on every subsequent keypress
@@ -4096,10 +4096,8 @@ fn completion(cx: &mut Context) {
     };
 
     let offset_encoding = language_server.offset_encoding();
-    let cursor = doc
-        .selection(view.id)
-        .primary()
-        .cursor(doc.text().slice(..));
+    let text = doc.text().slice(..);
+    let cursor = doc.selection(view.id).primary().cursor(text);
 
     let pos = pos_to_lsp_pos(doc.text(), cursor, offset_encoding);
 
@@ -4107,6 +4105,15 @@ fn completion(cx: &mut Context) {
 
     let trigger_offset = cursor;
 
+    // TODO: trigger_offset should be the cursor offset but we also need a starting offset from where we want to apply
+    // completion filtering. For example logger.te| should filter the initial suggestion list with "te".
+
+    use helix_core::chars;
+    let mut iter = text.chars_at(cursor);
+    iter.reverse();
+    let offset = iter.take_while(|ch| chars::char_is_word(*ch)).count();
+    let start_offset = cursor.saturating_sub(offset);
+
     cx.callback(
         future,
         move |editor: &mut Editor,
@@ -4129,7 +4136,7 @@ fn completion(cx: &mut Context) {
             };
 
             if items.is_empty() {
-                editor.set_error("No completion available".to_string());
+                // editor.set_error("No completion available".to_string());
                 return;
             }
             let size = compositor.size();
@@ -4137,7 +4144,14 @@ fn completion(cx: &mut Context) {
                 .find(std::any::type_name::<ui::EditorView>())
                 .unwrap();
             if let Some(ui) = ui.as_any_mut().downcast_mut::<ui::EditorView>() {
-                ui.set_completion(items, offset_encoding, trigger_offset, size);
+                ui.set_completion(
+                    editor,
+                    items,
+                    offset_encoding,
+                    start_offset,
+                    trigger_offset,
+                    size,
+                );
             };
         },
     );
diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index 6c9e3a80..ba009c50 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -69,14 +69,18 @@ impl menu::Item for CompletionItem {
 /// Wraps a Menu.
 pub struct Completion {
     popup: Popup<Menu<CompletionItem>>,
+    start_offset: usize,
+    #[allow(dead_code)]
     trigger_offset: usize,
     // TODO: maintain a completioncontext with trigger kind & trigger char
 }
 
 impl Completion {
     pub fn new(
+        editor: &Editor,
         items: Vec<CompletionItem>,
         offset_encoding: helix_lsp::OffsetEncoding,
+        start_offset: usize,
         trigger_offset: usize,
     ) -> Self {
         // let items: Vec<CompletionItem> = Vec::new();
@@ -175,16 +179,22 @@ impl Completion {
             };
         });
         let popup = Popup::new(menu);
-        Self {
+        let mut completion = Self {
             popup,
+            start_offset,
             trigger_offset,
-        }
+        };
+
+        // need to recompute immediately in case start_offset != trigger_offset
+        completion.recompute_filter(editor);
+
+        completion
     }
 
-    pub fn update(&mut self, cx: &mut commands::Context) {
+    pub fn recompute_filter(&mut self, editor: &Editor) {
         // recompute menu based on matches
         let menu = self.popup.contents_mut();
-        let (view, doc) = current!(cx.editor);
+        let (view, doc) = current_ref!(editor);
 
         // cx.hooks()
         // cx.add_hook(enum type,  ||)
@@ -200,14 +210,18 @@ impl Completion {
             .selection(view.id)
             .primary()
             .cursor(doc.text().slice(..));
-        if self.trigger_offset <= cursor {
-            let fragment = doc.text().slice(self.trigger_offset..cursor);
+        if self.start_offset <= cursor {
+            let fragment = doc.text().slice(self.start_offset..cursor);
             let text = Cow::from(fragment);
             // TODO: logic is same as ui/picker
             menu.score(&text);
         }
     }
 
+    pub fn update(&mut self, cx: &mut commands::Context) {
+        self.recompute_filter(cx.editor)
+    }
+
     pub fn is_empty(&self) -> bool {
         self.popup.contents().is_empty()
     }
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 0605e2c7..9234bb96 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -33,7 +33,7 @@ pub struct EditorView {
     keymaps: Keymaps,
     on_next_key: Option<Box<dyn FnOnce(&mut commands::Context, KeyEvent)>>,
     last_insert: (commands::Command, Vec<KeyEvent>),
-    completion: Option<Completion>,
+    pub(crate) completion: Option<Completion>,
     spinners: ProgressSpinners,
     autoinfo: Option<Info>,
 }
@@ -721,12 +721,21 @@ impl EditorView {
 
     pub fn set_completion(
         &mut self,
+        editor: &Editor,
         items: Vec<helix_lsp::lsp::CompletionItem>,
         offset_encoding: helix_lsp::OffsetEncoding,
+        start_offset: usize,
         trigger_offset: usize,
         size: Rect,
     ) {
-        let mut completion = Completion::new(items, offset_encoding, trigger_offset);
+        let mut completion =
+            Completion::new(editor, items, offset_encoding, start_offset, trigger_offset);
+
+        if completion.is_empty() {
+            // skip if we got no completion results
+            return;
+        }
+
         // TODO : propagate required size on resize to completion too
         completion.required_size((size.width, size.height));
         self.completion = Some(completion);
@@ -901,6 +910,7 @@ impl Component for EditorView {
                 EventResult::Consumed(None)
             }
             Event::Key(key) => {
+                cxt.editor.reset_idle_timer();
                 let mut key = KeyEvent::from(key);
                 canonicalize_key(&mut key);
                 // clear status
@@ -935,6 +945,7 @@ impl Component for EditorView {
                                     if callback.is_some() {
                                         // assume close_fn
                                         self.completion = None;
+                                        cxt.editor.clear_idle_timer(); // don't retrigger
                                     }
                                 }
                             }
@@ -948,6 +959,7 @@ impl Component for EditorView {
                                     completion.update(&mut cxt);
                                     if completion.is_empty() {
                                         self.completion = None;
+                                        cxt.editor.clear_idle_timer(); // don't retrigger
                                     }
                                 }
                             }
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index b08a2df2..5af6dbf3 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -9,10 +9,12 @@ use crate::{
 use futures_util::future;
 use std::{
     path::{Path, PathBuf},
+    pin::Pin,
     sync::Arc,
-    time::Duration,
 };
 
+use tokio::time::{sleep, Duration, Instant, Sleep};
+
 use slotmap::SlotMap;
 
 use anyhow::Error;
@@ -24,6 +26,14 @@ use helix_core::Position;
 
 use serde::Deserialize;
 
+fn deserialize_duration_millis<'de, D>(deserializer: D) -> Result<Duration, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let millis = u64::deserialize(deserializer)?;
+    Ok(Duration::from_millis(millis))
+}
+
 #[derive(Debug, Clone, PartialEq, Deserialize)]
 #[serde(rename_all = "kebab-case", default)]
 pub struct Config {
@@ -43,6 +53,9 @@ pub struct Config {
     pub smart_case: bool,
     /// Automatic insertion of pairs to parentheses, brackets, etc. Defaults to true.
     pub auto_pairs: bool,
+    /// Time in milliseconds since last keypress before idle timers trigger. Used for autocompletion, set to 0 for instant. Defaults to 400ms.
+    #[serde(skip_serializing, deserialize_with = "deserialize_duration_millis")]
+    pub idle_timeout: Duration,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
@@ -70,6 +83,7 @@ impl Default for Config {
             middle_click_paste: true,
             smart_case: true,
             auto_pairs: true,
+            idle_timeout: Duration::from_millis(400),
         }
     }
 }
@@ -91,6 +105,8 @@ pub struct Editor {
     pub status_msg: Option<(String, Severity)>,
 
     pub config: Config,
+
+    pub idle_timer: Pin<Box<Sleep>>,
 }
 
 #[derive(Debug, Copy, Clone)]
@@ -125,10 +141,24 @@ impl Editor {
             registers: Registers::default(),
             clipboard_provider: get_clipboard_provider(),
             status_msg: None,
+            idle_timer: Box::pin(sleep(Duration::from_millis(500))),
             config,
         }
     }
 
+    pub fn clear_idle_timer(&mut self) {
+        // equivalent to internal Instant::far_future() (30 years)
+        self.idle_timer
+            .as_mut()
+            .reset(Instant::now() + Duration::from_secs(86400 * 365 * 30));
+    }
+
+    pub fn reset_idle_timer(&mut self) {
+        self.idle_timer
+            .as_mut()
+            .reset(Instant::now() + Duration::from_millis(500));
+    }
+
     pub fn clear_status(&mut self) {
         self.status_msg = None;
     }
diff --git a/helix-view/src/macros.rs b/helix-view/src/macros.rs
index c9a04270..0bebd02f 100644
--- a/helix-view/src/macros.rs
+++ b/helix-view/src/macros.rs
@@ -44,3 +44,19 @@ macro_rules! view {
         $( $editor ).+ .tree.get($( $editor ).+ .tree.focus)
     }};
 }
+
+#[macro_export]
+macro_rules! doc {
+    ( $( $editor:ident ).+ ) => {{
+        $crate::current_ref!( $( $editor ).+ ).1
+    }};
+}
+
+#[macro_export]
+macro_rules! current_ref {
+    ( $( $editor:ident ).+ ) => {{
+        let view = $( $editor ).+ .tree.get($( $editor ).+ .tree.focus);
+        let doc = &$( $editor ).+ .documents[view.doc];
+        (view, doc)
+    }};
+}